Shortround6
Major General
Basically, to get any worthwhile number of R-2800 powered fighters in 1942 ( hundreds not dozens), you have to kill the B-26 program. You need both the engines and props and there is nothing else to take them from. Now if you do this you reduce the numbero f twin engine medium bombers available to the USAAC by about 1/2 in 1942. Now maybe you can get Martin to build B-25s and squeeze another 1500-2000 R-2600s out of Wright.
And look again at what you get. Everybody seems to be mesmerized by the take-off power of the early R-2800 and R-2600.
The Allison -39 offered 1150hp at 12,000ft for hundreds of pounds less weight (even including radiator and coolant) and less drag and the Merlin V-1650-1 offered 1250hp at 15,600ft in March of 1941 ( before any were actually delivered) also at less weight and drag.
at 12,000ft the R-2600B is offering 1450hp, the R-2800s are offering 1500hp at 14,000ft and 1600hp at 13,500ft. at 15,500 they are offering about 1425hp and 1500hp. at 18500ft where the V-1650-1 delivered 1120hp the R-2600B offered (if you extend the lines) about 1150hp and the two R-2800s delivered around 1250-1275hp and 1325hp? The "B" series R-2800 is delivering about 18% more power at 18,500ft to make up for it's weight and drag compared to the 53% advantage it had at sea level or for take-off. The "A" series R-2800 engine offers even less of an advantage at 18,500ft.
Once Allison straightened out the gear problem the later Allisons were good for 1125hp at 15,500ft and that may be what Allison promised on the earlier failed engine when the "planners" were making decisions. "A" series R-2800 offering 26% more power at 15,500ft than a high geared Allison but at about 900-100lbs more weight (not including radiator and coolant) and the bigger propeller, bigger oil system, etc. Plus a LOT more drag.
And look again at what you get. Everybody seems to be mesmerized by the take-off power of the early R-2800 and R-2600.
The Allison -39 offered 1150hp at 12,000ft for hundreds of pounds less weight (even including radiator and coolant) and less drag and the Merlin V-1650-1 offered 1250hp at 15,600ft in March of 1941 ( before any were actually delivered) also at less weight and drag.
at 12,000ft the R-2600B is offering 1450hp, the R-2800s are offering 1500hp at 14,000ft and 1600hp at 13,500ft. at 15,500 they are offering about 1425hp and 1500hp. at 18500ft where the V-1650-1 delivered 1120hp the R-2600B offered (if you extend the lines) about 1150hp and the two R-2800s delivered around 1250-1275hp and 1325hp? The "B" series R-2800 is delivering about 18% more power at 18,500ft to make up for it's weight and drag compared to the 53% advantage it had at sea level or for take-off. The "A" series R-2800 engine offers even less of an advantage at 18,500ft.
Once Allison straightened out the gear problem the later Allisons were good for 1125hp at 15,500ft and that may be what Allison promised on the earlier failed engine when the "planners" were making decisions. "A" series R-2800 offering 26% more power at 15,500ft than a high geared Allison but at about 900-100lbs more weight (not including radiator and coolant) and the bigger propeller, bigger oil system, etc. Plus a LOT more drag.